package com.bigshen.algorithm.lString.solution01ReverseWordsInAString;

/**
 *151. Reverse Words in a String 151. 翻转字符串里的单词
 *Given an input string s, reverse the order of the words.
 *
 * A word is defined as a sequence of non-space characters. The words in s will be separated by at least one space.
 *
 * Return a string of the words in reverse order concatenated by a single space.
 *
 * Note that s may contain leading or trailing spaces or multiple spaces between two words. The returned string should only have a single space separating the words. Do not include any extra spaces.
 *
 *  
 *
 * Example 1:
 * Input: s = "the sky is blue"
 * Output: "blue is sky the"
 *
 * Example 2:
 * Input: s = "  hello world  "
 * Output: "world hello"
 * Explanation: Your reversed string should not contain leading or trailing spaces.
 *
 * Example 3:
 * Input: s = "a good   example"
 * Output: "example good a"
 * Explanation: You need to reduce multiple spaces between two words to a single space in the reversed string.
 *
 * Example 4:
 * Input: s = "  Bob    Loves  Alice   "
 * Output: "Alice Loves Bob"
 *
 * Example 5:
 * Input: s = "Alice does not even like bob"
 * Output: "bob like even not does Alice"
 *
 * Constraints:
 *
 * 1 <= s.length <= 104
 * s contains English letters (upper-case and lower-case), digits, and spaces ' '.
 * There is at least one word in s.
 *
 * 来源：力扣（LeetCode）
 * 链接：https://leetcode-cn.com/problems/reverse-words-in-a-string
 * 著作权归领扣网络所有。商业转载请联系官方授权，非商业转载请注明出处。
 */
public class Solution {
    // 双指针 or 新数组遍历填充
    public String reverseWords(String s) {
        if (null == s || s.trim().length() == 0) {
            return s;
        }
        String[] array = s.trim().split(" ");

        StringBuffer sb = new StringBuffer();

        for (int i = array.length-1; i > -1; i --) {
            if (array[i].trim().length() == 0) {
                continue;
            }
            sb.append(array[i] + " ");
        }

        return sb.toString().trim();
    }
}
